- Last Update On : 2013-02-26
The Jo-1 antigen resides on the enzyme, histidyl-tRNA synthetase, which is usually located in the cytoplasm of cells, rather than the nucleus. Antibodies to the Jo-1 antigen are detected in approximately 25% of adult patients with myositis including; polymyositis, dermatomyositis, and overlap syndromes. Jo-1 antibodies are most commonly found in patients (68%) with a combination of myositis and interstitial pulmonary fibrosis. Patients with Jo-1 antibodies may have a negative ANA, for the same reasons described for SS-A/Ro antibodies.
Specimen requirement is one red top tube of blood.